Question

我有一个变量var =“ TAG：***原因：绕行*** SSC” 我必须将此变量放在双引号之间，否则它将***更改为我的主目录中的文件

$ var="TAG: *** Reason:Circumvention *** SSC"
$ echo $var
TAG: sqlnet.log test.sh tst.sh Reason:Circumvention sqlnet.log test.sh tst.sh SSC
$ echo "$var"
TAG: *** Reason:Circumvention *** SSC

现在，我想将所有*更改为另一个字符（例如<），并将其放入新变量中（这样我就不必再将其放在双引号中了），但似乎它将整个变量替换为<。如何避免这种情况？

$ echo "$var"
TAG: *** Reason:Circumvention *** SSC
$ newvar="${var//*/<}"
$ echo $newvar
<

Answer 1

引用bash下的Pattern Matching手册

模式匹配

   Any character that appears in a pattern, other than the special pattern characters described below, matches itself. The NUL character may not occur in a pattern.   A  backslash
   escapes the following character; the escaping backslash is discarded when matching.  The special pattern characters must be quoted if they are to be matched literally.

   The special pattern characters have the following meanings:

          *      Matches any string, including the null string.  When the globstar shell option is enabled, and * is used in a pathname expansion context, two adjacent *s used as a
                 single pattern will match all files and zero or more directories and subdirectories.  If followed by a /, two adjacent *s will match only directories and subdirec-
                 tories.

可以转义*或将其放在单引号中。

var="TAG: *** Reason:Circumvention *** SSC"
newvar=${var//\*/<}          
echo "$newvar"

或

newvar=${var//'*'/<}

全局*将从头到尾匹配所有字符/字符串，并用参数扩展替换中的所有字符/字符串替换，在这种情况下为<符号。

在bash脚本的变量中用<替换*，

1 个答案: